I have had a few and they were good razors. "Weltruf" means world-wide or world-reknowned, meaning that the razor has a world-wide reputation/trademark. I don't know what "shaber" means, but the line "Schnurrbart Schaber & Hat Weltruf" means "moustache ..... and has a world-wide reputation."
"Silberstahl" is simply "silver-steel" - a bright, hard, high-carbon steel alloy with no actual silver in it now, often used for fine tools (for what it is worth and notwithstanding any of the ill-informed tripe you may read to the contrary on other forums, the very early silver steel did indeed contain silver - it was invented by Michael Faraday and he gave samples of razors and ingots of the alloy to a number of razor makers - one Sheffield maker even produced a small booklet on the silver steel razors he produced using Faraday's formulation. Apparently it did not offer any real advantages though, (the original experiment was to make steel less prone to rusting, etc), but the name 'stuck' for any bright-faced steel even if it did not contain silver.
The make is quite old, and is registered to "Jaguar" Stahlwarenfabrik GmbH & Co. KG - at least since 1979, when they renewed the world-symbol trademark.
Some of the early (late 1920s or 1930s) blades had a curious grind - instead of the hollow being from top of spine to cutting edge, it followed the spine, so it was ground at a 90 degree angle to the common way of grinding.
I would imagine that the scales are imitation ivory - rubbing them briskly with a silky or satin cloth may make them emit a peculiar odour: if it is a bit like camphor (eg, like "Vick") or vinegary they are probably some sort of celluloid (there were at least two different types used for scales, with two different smells - the camphor-smelling ones are later than the vinegary smelling ones). The "hot needle test" is usually definitive for real ivory as opposed celluloid, but can realy damage celluloid if not done with caution - the very early celluloids can catch fire in a spectacular way!
Regards,
Neil